Numerical analysis of thermal-hydraulic characteristics of the whole LFR core under blockage conditions

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2024-09-23 DOI:10.1016/j.ijthermalsci.2024.109435

Jiacheng Yu, Kai Liu, Hanrui Qiu, Mingjun Wang, Wenxi Tian, G.H. Su

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Abstract

Blockage accidents are critical scenarios in the design and safety analysis of lead-bismuth cooled fast reactor (LFR) core. Traditional analysis of blockage accidents in LFR focuses on localized, fine-scale computational fluid dynamics (CFD) simulations of single or three assemblies, but the analysis of the whole core scale impact caused by blockage accidents is insufficient. Therefore, this paper uses CorTAF-LBE, a three-dimensional thermal-hydraulic analysis code developed by XJTU-NuTHeL, to analyze the impact of blockage accidents on the whole core of the LFR. The reliability of the code in calculating thermal-hydraulic parameters under blockage accidents was validated based on the KALLA-THEADES and KALLA-IWF experiments. Taking the MYRRHA-FASTEF core as the object, simulations and analyses are conducted for various blockage scenarios with different lengths and positions. The results indicate that blockage accidents lead to an enlarged coolant temperature gradient at the core outlet. Lengthening the blockage results in an elevation of the peak temperature in the cladding. Under 2.06 % blockage at the center of the assembly, blockage in the middle of the heating segment poses the greatest threat to cladding integrity, with the maximum temperature reaching 1336.9K, an increase of 635.4K compared to normal operating conditions. Under 4.59 % blockage at the edge of the assembly, the maximum cladding temperature reaches 1381.8K, and the heat transfer rate of the inter-wrapper flow (IWF) adjacent to the blockage area is 24.2 % higher than under normal operation. Additionally, severe degradation in heat transfer downstream was not observed in several simulated blockage scenarios.

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堵塞条件下整个低温冷冻机堆芯热液压特性的数值分析

堵塞事故是铅铋冷却快堆（LFR）堆芯设计和安全分析中的关键情景。传统的快堆堆芯堵塞事故分析侧重于单个或三个组件的局部、精细尺度计算流体动力学（CFD）模拟，但对堵塞事故造成的整个堆芯尺度的影响分析不足。因此，本文采用西安交大-核动力院开发的三维热工水力分析代码 CorTAF-LBE 来分析堵塞事故对长征四号乙运载火箭整个堆芯的影响。在KALLA-THEADES和KALLA-IWF试验的基础上，验证了该代码在堵塞事故下计算热液参数的可靠性。以 MYRRHA-FASTEF 堆芯为对象，对不同长度和位置的各种堵塞情况进行了模拟和分析。结果表明，堵塞事故会导致堆芯出口处的冷却剂温度梯度增大。加长堵塞会导致包壳的峰值温度升高。在组件中心堵塞率为 2.06% 的情况下，加热段中部的堵塞对堆芯完整性的威胁最大，最高温度达到 1336.9K，比正常运行条件下增加了 635.4K。在组件边缘 4.59% 的阻塞情况下，包层最高温度达到 1381.8K，阻塞区域附近的包层间流 (IWF) 热传导率比正常运行条件下高 24.2%。此外，在几种模拟堵塞情况下都没有观察到下游传热的严重退化。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.